2.66 Ethel McLennan : 



aleurone layer at this end of the grain cut tangentially. and there- 

 fore it does not appear as a single layer of cells.) Interpolated be- 

 tween the aleurone cells, lying in the inter-cellular spaces, alter- 

 ing their whole contour, are outlines of hyphae, whicli seem to be 

 swollen, somewhat gelatinised, and in a state of disorganisation. 

 Similar bodies were also visible in the matrix of the Cflls them- 

 selves. 



These occurrences lead me to believe that at some stage in the 

 life of the grain tlie hyphae were intra-cellular, and that in the 

 few aberrant cases met witli this embryohigical condition persisted 

 in the mature grain. 



JJevelopi/ienf of tJie Orart/ from the Flotri r'uKj to the Fruiting 



St (I fie . 



It is convenient to divide this portion of the paper into sections, 

 and to consider the i-elation of the fungus to tlie grain, at certain 

 definite stages in its formation. This relation becomes very pro- 

 nounced and charactei-istic, either just about the fertilisation 

 period or inmiediately afterwards, and from here to the final stages 

 is most intimately associated with the changes taking place, result- 

 ing in the formation of the endosperm, witli its aleurone layer, and 

 the various parts of tlie embryo. 



St(i!/f^ A. 



Text-figure 4 illustrates the external appearance c>f the 

 ovary at the flowering stage just prior to fertilisatioti. It is 

 drawn from the ventral surface, and shows tlie stigmas arising from 

 the dorsal side, the bi-carpellai-y nature of the fruit is indicated in 

 the figure. The ovum lies directed towards tliy proximal end of the 

 ovary. I have designated this period Stage A. 



Hyphae are present in the carpels from their earliest inception, 

 but it is only at about tjiis stage that theii- intimate relation with 

 the ovarian tissues of the grass is evident. They enter the ovary 

 at the stalk end, and branch through the carpellary wall. They 

 are generally nioi-f abundant during the eai'lier stages at this end 

 than at the distal stigmatic end. These hyphae characteristically 

 accompany tlie vascular tissue of the stalk, and are to be seen in 

 very close liroximity to the annular and spiral vessels running m 

 this area. (Plate XXI. Fig. 4.) In many of the sections numerous 

 small lateral buds on the hyphae suggested haustoria, but thev may 

 be minute lateral liranches just lieing caught in tlie section. The 



